Farsi is Indo-European. Morphologically it's fairly simple (e.g. you have different verb forms for person and number, but not for gender) --- except that some people like to apply Arabic morphology to Arabic loanwords in certain cases (analogous to how some show-offs use obscure Greek plural paradigms like "metropolei" instead of "metropolises" when speaking English).
The writing system's a bit of a pain --- short vowels aren't indicated, and it preserves etymological spelling for Arabic loanwords even though a lot of these sound distinctions have been lost in speech. (Tajik --- the variant of Farsi spoken in Tajikistan, ex-USSR country --- largely eliminated that problem, though, by writing in Cyrillic instead of Arabic script).
Hebrew and Aramaic definitely get a special “so many frigging affixes that it takes half an hour to figure out the root before you can look up the frigging word in the dictionary” award in my book. I assume I would feel the same way about Arabic if I ever learned enough of it to even attempt to use an Arabic dictionary.
(I should note, though, that while Farsi and Arabic use the same writing system, they are from different language families.)
On the other hand, once you understand how to construct & deconstruct words, it's a lot easier to build your vocabulary.
You learn the word "read" & you immediately know all the verb tenses (read, reading), the nouns (food) the adjectives (written). Inconsistencies & exceptions make going from conversational to fluent a nightmare, but getting to conversational is not too bad.
Affixes, like an new alphabet are a bit of a hurdle, but once you're over it it's not hard any more.
Arabic is a hell of language to learn. Even as an Egyptian born in a semi-Arabic speaking house, and in the middle of trying to teach myself the language, I'm finding Arabic really difficult to learn. My two main problems are: a) Many words are not actually written as one word, and so you might have 2 or 3 separated strings of letters that are meant to be read altogether as one, which is ridiculously confusing - and - B) Arabic is commonly written with the vowels omitted. Most Arabic words have a set of unique root consonants, usually 3 or 4 consonants, that help you identify the word you're reading. So they'll eliminate the vowels because the root consonants and modifiers should be sufficient for word recognition. This probably makes reading script faster as there's less to process, and I'm sure it does, but as a beginner, it's tough.
Arabic is a hell of language to learn. Even as an Egyptian born in a semi-Arabic speaking house...I'm finding Arabic really difficult to learn.
You're not alone. The US Defense Language Institute teaches many languages, mostly to native English speakers. Of the languages they teach, Arabic takes the longest.
It's a shame the article didn't list the number of weeks the DLI spends on each of the languages. It "only" covers a few dozen languages, but course length would be an excellent proxy for language difficulty for English speakers.
As a data point, I attended DLI in 1991-1992 for Russian. At the time the basic Russian class lasted for 47 weeks..5 days a week, 8 hours a day. If I remember correctly, Arabic was 63 weeks.
DLI 'ranked' languages according to difficulty...categories (cats) I-V. Russian was a III. Arabic was cat IV. The only two cat V languages were English (for non-natives) and Japanese.
Also, Arabic calligraphy varies greatly, and just because you know one form doesn't enable you to read another. Perhaps cursive vs. print is similarly difficult for non-English speakers, but I feel as if Arabic's is especially difficult. After years of studying the language, I can hardly do anything with it.
Yeah, I should've included that as a third point. We get Arabic television stations at home that I'll watch to try to read headlines, etc, for practice, but the font changes so drastically from show to show that I often find some letters unrecognizable.
What about the fact that the standard written/literary form is not what people actually speak? Arabic speakers seem so strict about the language. I would imagine that makes things hard.
Also, would point out that Greek and Latin are not "cousins" to English, more like great-grandfathers, given the large amount of borrowing from both.